Halloween, observed October 31, is the eve of the Christian feast of All Hallows' Day (All Saints' Day). It originates from the ancient Celtic festival of Samhain and is most famously celebrated in the United States, Canada, Ireland, and the UK with costumes, trick-or-treating, and themed decorations.
Samhain marked the end of harvest and the beginning of winter in pre-Christian Celtic Ireland — a liminal time when boundaries between living and dead thinned. Christianity moved All Saints' Day to November 1 in the 9th century, absorbing Samhain customs into a Christianized framework. Irish immigrants brought the customs to North America in the 19th century, where they evolved into modern Halloween.
Trick-or-treating: children in costume go door to door collecting candy. Jack-o'-lanterns: pumpkins carved with faces and lit. Costume parties, haunted houses, horror movie marathons. Black, orange, and purple decor; spiders, witches, ghosts, vampires, skeletons.
Candy of all kinds. Pumpkin pie, pumpkin spice everything. Caramel apples. Hot apple cider. Soul cakes (UK/Ireland traditional).
"Happy Halloween!" · "Trick or treat!"
Halloween is not a public holiday — businesses operate normally. Major US and Canadian cities hold large costume parades. New Orleans, Salem (Massachusetts), and Las Vegas are famous Halloween destinations.
This holiday is also publicly observed in: